Class / Patent application number | Description | Number of patent applications / Date published |
381710110 | Adaptive filter topology | 87 |
20080232607 | ROBUST ADAPTIVE BEAMFORMING WITH ENHANCED NOISE SUPPRESSION - A novel adaptive beamforming technique with enhanced noise suppression capability. The technique incorporates the sound-source presence probability into an adaptive blocking matrix. In one embodiment the sound-source presence probability is estimated based on the instantaneous direction of arrival of the input signals and voice activity detection. The technique guarantees robustness to steering vector errors without imposing ad hoc constraints on the adaptive filter coefficients. It can provide good suppression performance for both directional interference signals as well as isotropic ambient noise. | 09-25-2008 |
20080317256 | Method for Reproducing a Secondary Path in an Active Noise Reduction System - A method for reproducing a secondary path in an active noise reduction system comprising a transmission path (S, | 12-25-2008 |
20090147966 | Method and Apparatus for In-Ear Canal Sound Suppression - An earpiece ( | 06-11-2009 |
20090208028 | ADAPTIVE FILTER IN A SENSOR ARRAY SYSTEM - Disclosed is a steerable sensor array that receives input from a target and applies an averaging filter. An adaptive filter is then used if the SNR of the output of the averaging filter reaches a threshold. | 08-20-2009 |
20090220102 | Active Noise Reduction Adaptive Filter Leakage Adjusting - An active noise reduction system using adaptive filters. A method of operation the active noise reduction system includes smoothing a stream of leakage factors. The frequency of a noise reduction signal may be related to the engine speed of an engine associated with the system within which the active noise reduction system is operated. The engine speed signal may be a high latency signal and may be obtained by the active noise reduction system over audio entertainment circuitry. | 09-03-2009 |
20090257601 | ACOUSTIC SPEAKER SYSTEM WITH STRONG BASS CAPABILITY - Sound reproduction systems are described that have superior response to pure bass frequency signals from musical instruments such as electric bass guitar and string bass. A first amplifier drives a low frequency woofer and a second amplifier drives a full range speaker system. The bass component of the audio signal handled by the second amplifier is monitored and progressively compressed as the bass energy approaches a critical level that may damage one or more elements of the full range speaker. Speaker protection devices are also described that passively limit damaging pulses into speakers typically caused by plugging in equipment. | 10-15-2009 |
20090304200 | Adaptive mode control apparatus and method for adaptive beamforming based on detection of user direction sound - An adaptive mode control apparatus and method for adaptive beamforming based on detection of a user direction sound are provided. The adaptive mode control apparatus includes a signal intensity detector that searches for signal intensity of each designated direction to detect signal intensity having a maximum value when a voice signal of each direction is input through at least one microphone; and an adaptive mode controller that compares the signal intensity having the maximum value detected through the signal intensity detector with a threshold value and determines whether to perform an adaptive mode of a Generalized Sidelobe Canceller (GSC) according to the comparison results. Therefore, a lack of control of adaptation of an adaptive filter of the conventional art is solved. That is, as one condition for guaranteeing performance of adaptive beamforming, adaptation of an adaptive filter is not performed when noise of a sound with a high autocorrelation is cancelled. | 12-10-2009 |
20100014685 | ADAPTIVE NOISE CONTROL SYSTEM - An active noise cancellation system that reduces, at a listening position, power of a noise signal radiated from a noise source to the listening position. The system includes an adaptive filter, at least one acoustic actuator and a signal processing device. The adaptive filter receives a reference signal representing the noise signal, and provides a compensation signal. The at least one acoustic actuator radiates the compensation signal to the listening position. The signal processing device evaluates and assesses the stability of the adaptive filter. | 01-21-2010 |
20100020981 | SPECTRAL CONTENT MODIFICATION FOR ROBUST FEEDBACK CHANNEL ESTIMATION - The invention relates to a listening device for processing an input sound to an output sound according to a user's needs. The invention further relates to a method of reducing acoustic feedback in a listening device and to the use of a listening device. The object of the present invention is to provide an alternative scheme for feedback estimation in a listening device. The problem is solved in that the listening device comprises an input transducer for converting an input sound to an electric input signal, and an output transducer for converting a processed electric output signal to an output sound, a forward path being defined between the input transducer and the output transducer and comprising a signal processing unit adapted for processing an SPU-input signal originating from the electric input signal in a time-frequency representation comprising successive time frames each comprising a frequency spectrum of the signal in the time frame in question, the signal processing unit defining an input side and an output side of the forward path and comprising a spectral content modification unit adapted for modifying values of the signal of one or more regions of the frequency spectrum of a given time frame to provide that the modified values are less correlated to the corresponding time-frequency regions of the input signal than the unmodified output signal thereby providing an improved processed output signal, and a feedback loop from the output side to the input side comprising a feedback path estimation unit for estimating the effect of acoustic feedback from the output transducer to the input transducer, wherein the feedback path estimation unit is adapted to use the improved processed output signal in the estimation. This has the advantage of providing a better accuracy vs. tracking speed trade-off of the feedback path estimate. The invention may e.g. be used for listening devices prone to acoustic feedback, e.g. hearing aids, headsets or active earplugs. | 01-28-2010 |
20100027804 | NOISE CONTROL DEVICE - To provide a noise control device capable of eliminating a possibility that a noise arriving at a control point is increased as compared to a case where the noise control is not performed and capable of reducing the circuit scale thereof. The noise control device according to the present invention includes: a controlling noise detector for detecting a given arriving noise to output a controlling noise signal; a controlling filter section for signal-processing the controlling noise signal outputted from the controlling noise detector, by using a fixed filter coefficient which is preset, to output a control signal; a control speaker for reducing the given noise arriving at the control point, by emitting toward the control point a control sound based on the control signal outputted from the controlling filter section; a noise determination section for determining whether or not the given noise arriving at the control point is a noise corresponding to the fixed filter coefficient; and an output control section for stopping output of the control signal from the controlling filter section when the noise determination section determines that the given noise is not a noise corresponding to the fixed filter coefficient. | 02-04-2010 |
20100034398 | METHOD FOR THE ACTIVE REDUCTION OF SOUND DISTURBANCE - A method and a system for the active reduction, at a predetermined area, of the energy of a sound signal (d | 02-11-2010 |
20100092004 | LOUDSPEAKER DEVICE - The loudspeaker device according to the present invention comprises a loudspeaker; a feedforward processing section for performing feedforward processing on an electric signal to be inputted to the loudspeaker based on a preset filter coefficient so that non-linear distortion which occurs from the loudspeaker is removed; and a feedback processing section for detecting vibration of the loudspeaker, and performing feedback processing on an electric signal concerning the vibration with respect to the electric signal to be inputted to the loudspeaker. The feedback processing section performs feedback processing on the electric signal concerning the vibration so that the non-linear distortion which occurs from the loudspeaker is removed and so that a frequency characteristic concerning the vibration of the loudspeaker becomes a predetermined frequency characteristic. | 04-15-2010 |
20100098263 | ACTIVE NOISE REDUCTION ADAPTIVE FILTER LEAKAGE ADJUSTING - A method for determining leakage factors or adaptation rates, or both, for adaptive filters in an active noise reduction system. The leakage factor or adaptation rate, or both, may vary depending on a parameter of an input reference signal. The parameter may include one or more of reference signal input frequency, rate of change of reference input signal frequency, if a predetermined triggering condition exits, or if a predetermined event has occurred. | 04-22-2010 |
20100124337 | QUIET ZONE CONTROL SYSTEM - An active noise control system generates an anti-noise signal to drive a speaker to produce sound waves to destructively interfere with an undesired sound in a quiet zone. The anti-noise signal is generated with an adaptive filter having filter coefficients. The coefficients of the adaptive filter may be adjusted based on a first filter adjustment from a first listening region, and a second filter adjustment from a second listening region. A first weighting factor may be applied to the first filter adjustment, and a second weighting factor may be applied to the second filter adjustment. The first and second weighting factors may dictate the location and size of the quiet zone as being outside or partially within at least one of the first listening region and the second listening region. | 05-20-2010 |
20100150369 | FILTER APPARATUS FOR ACTIVELY REDUCING NOISE - A filter apparatus for reducing noise from a primary noise source, comprising a secondary source signal connector for generating secondary noise to reduce said primary noise and a sensor connector for connecting to a sensor for measuring said primary and secondary noise as an error signal. A first control filter is arranged to receive a reference signal and calculate a control signal for the secondary source signal. A second control filter is arranged to receive a delayed reference signal and calculate an auxiliary control signal; wherein an adaptation circuit is arranged to adapt said second control filter while receiving an error signal as a sum of the auxiliary control signal and an auxiliary noise signal. The auxiliary noise signal is constructed from a difference of the delayed filtered error signal and a delayed control signal. The first control filter is updated by a copy of said updated second control filter. | 06-17-2010 |
20100172511 | ACTIVE SILENCER AND METHOD FOR CONTROLLING ACTIVE SILENCER - An active silencer includes: a speaker generating control sound which interferes with noise; a microphone detecting noise remaining after the interference as a remaining noise signal; a sound quality evaluation unit evaluating the sound quality of the remaining noise and output a result of the sound quality evaluation; an actuation signal determination unit determining, according to the result of the sound quality evaluation, the detection timing of the frequency component of the remaining noise signal to be used when the control sound is generated for a plurality of bands of the remaining noise, corresponding to the plurality of bands of a reference signal corresponding to the noise; and a control signal generation unit generating and output a control signal for generation of the control sound depending on a plurality of bands of the determined remaining noise signal and a plurality of bands of the reference signal corresponding to the noise. | 07-08-2010 |
20100177905 | SYSTEM FOR ACTIVE NOISE CONTROL WITH PARALLEL ADAPTIVE FILTER CONFIGURATION - An active noise control system includes a plurality of adaptive filters. The plurality of adaptive filters each receives an input signal representative of an undesired sound. The adaptive filters may each generate an output signal based on the input signal. The output signals are used to generate an anti-noise signal configured to drive a speaker to produce sound waves to destructively interfere with the undesired sound. | 07-15-2010 |
20100183165 | NOISE CANCELLING DEVICE AND METHOD, AND NOISE CANCELLING PROGRAM - [Problems] To detecting divergence of a coefficient of an adaptive filter without setting a threshold value in advance based on characteristics of a device from which a noise is to be cancelled or an environment. | 07-22-2010 |
20100195844 | ADAPTIVE NOISE CONTROL SYSTEM - An active noise cancellation system includes an adaptive filter, a signal source, an acoustic actuator, a microphone, a secondary path and an estimation unit. The adaptive filter receives a reference signal representing noise, and provides a compensation signal in response to the received reference signal. The signal source provides a measurement signal. The acoustic actuator radiates the compensation signal and the measurement signal to the listening position. The microphone receives a first signal that is a superposition of the radiated compensation signal, the radiated measurement signal, and the noise signal at the listening position, and provides a microphone signal in response to the received first signal. The secondary path includes a secondary path system that represents a signal transmission path between an output of the adaptive filter and an output of the microphone. The estimation unit estimates a transfer characteristic of the secondary path system in response to the measurement signal and the microphone signal. | 08-05-2010 |
20100310085 | APPARATUS FOR PROCESSING AN AUDIO SIGNAL AND METHOD THEREOF - A method of processing an audio signal is disclosed. The present invention includes receiving, by an audio processing apparatus, an input signal; estimating indicator function using a signal power of the input signal; obtaining an adapted filter using the indicator function and an equalization filter; and, generating an output signal by applying the adapted filter to the input signal. | 12-09-2010 |
20100310086 | NOISE CANCELLATION SYSTEM WITH LOWER RATE EMULATION - There is provided a noise cancellation system, comprising: an input for a digital signal, the digital signal having a first sample rate; a digital filter, connected to the input to receive the digital signal; a decimator, connected to the input to receive the digital signal and to generate a decimated signal at a second sample rate lower than the first sample rate; and a processor. The processor comprises: an emulation of the digital filter, connected to receive the decimated signal and to generate an emulated filter output; and a control circuit, for generating a control signal on the basis of the emulated filter output. The control signal is applied to the digital filter to control a filter characteristic thereof. | 12-09-2010 |
20100329474 | HOWLING SUPPRESSION DEVICE, HOWLING SUPPRESSION METHOD, PROGRAM, AND INTEGRATED CIRCUIT - To provide a howling suppression device which can reduce quality deterioration of processed sound involved in howling suppression in an acoustic feedback loop environment. | 12-30-2010 |
20110019835 | Speaker Localization - The present invention relates to a method for localizing a sound source, in particular, a human speaker, comprising detecting sound generated by the sound source by means of a microphone array comprising more than two microphones and obtaining microphone signals, one for each of the microphones, selecting from the microphone signals a pair of microphone signals for a predetermined frequency range based on the distance of the microphones to each other and estimating the angle of the incidence of the sound on the microphone array based on the selected pair of microphone signals. | 01-27-2011 |
20110026725 | METHOD FOR MONITORING THE INFLUENCE OF AMBIENT NOISE ON STOCHASTIC GRADIENT ALGORITHMS DURING IDENTIFICATION OF LINEAR TIME-INVARIANT SYSTEMS - A hearing aid system and a method of estimating ambient noise in a listening device includes an input transducer and an output transducer, an electrical forward path between the input transducer and the output transducer providing a forward gain, an electrical feedback path comprising an adaptive filter for estimating the acoustic feedback gain from the output transducer to the input transducer. A method determines the quality of a critical gain measurement for a listening device. The method comprises a) monitoring the energy of the first-difference of the filter coefficients of the adaptive filter over time and b) applying a predefined threshold criterion to the change in energy content from one time instance to another to determine an acceptable impact of the ambient noise. This technique may e.g. be used for the fitting of hearing instruments where background noise is variable. | 02-03-2011 |
20110091047 | Active Noise Control in Mobile Devices - A three dimensional area of quiet is created by an active noise cancellation system comprising a reference microphone receiving background noise and sending the noise signal to an adaptive active noise canceller. An adaptive filter system using weights updated by a least mean squares method or other method generates an anti-phase signal which is broadcasted to counteract the background noise. The resulting residual noise or residual signal is sent back to the adaptive active noise canceller to reset the weights of the adaptive filter. | 04-21-2011 |
20110096937 | MICROPHONE APPARATUS AND SOUND PROCESSING METHOD - A microphone apparatus is provided, including a body, a main microphone and a reference microphone. The main microphone and a reference microphone are disposed on the body for receiving a sound from a source and a noise from other than the source, wherein the main microphone and the reference microphone are arranged vertically towards the source. | 04-28-2011 |
20110129098 | ACTIVE NOISE CANCELLATION - This document discusses, among other things, systems and methods for active noise cancellation. One example system includes a digital ANC circuit configured to receive first audio information from a first microphone and to produce an a digital anti-noise signal configured to attenuate noise sensed by the first microphone; an analog ANC circuit configured to receive second audio information from a second microphone and to produce an analog anti-noise signal configured to attenuate noise sensed by the second microphone; and wherein the system is configured to receive an intended audio signal and to provide an output signal for a speaker using the intended audio signal, the analog anti-noise signal, and the digital anti-noise signal. | 06-02-2011 |
20110135107 | Dual Adaptive Structure for Speech Enhancement - A clear, high quality voice signal with a high signal-to-noise ratio is achieved by use of an adaptive noise reduction scheme with two microphones in close proximity. The method includes the use of two omini directional microphones in a highly directional mode, and then applying an adaptive noise cancellation algorithm to reduce the noise. | 06-09-2011 |
20110216910 | ADAPTIVE NOTCH FILTER WITH VARIABLE BANDWIDTH, AND METHOD AND APPARATUS FOR CANCELING HOWLING BY USING THE ADAPTIVE NOTCH FILTER WITH VARIABLE BANDWIDTH - A variable-bandwidth adaptive notch filter which cancels howling from an input signal with a bandwidth varying according to a howling frequency to generate an output signal. | 09-08-2011 |
20110249827 | Systems and Methods for Improving the Intelligibility of Speech in a Noisy Environment - One aspect of the invention provides a method for enhancing speech output by an electro-acoustical transducer in a noisy listening environment. In some embodiments, this method includes: filtering an input audio signal x(t) using a filter H(z) to produce a filtered audio signal x(t) formula (I), wherein x(t) formula (I)—H(z)x(t); providing to an electro-acoustical transducer a signal corresponding to the filtered audio signal x(t) formula (I) to produce a sound wave corresponding to the filtered audio signal; and prior to filtering the audio signal using the filter, configuring the filter such that, with respect to one or more frequencies, the filtered audio signal has a higher signal level than the input audio signal, and such that the overall signal level of the filtered audio signal (sl | 10-13-2011 |
20110293105 | EARPIECE AND A METHOD FOR PLAYING A STEREO AND A MONO SIGNAL - An earpiece for providing an audio signal to two ears of a user, includes an audio interface for providing the audio signal, a bone conduction speaker coupled to the audio interface for outputting an output signal, an adaptive filter with an adjustable impulse response to provide a filtered signal that once played to the second ear of a user, by an in-ear speaker, reduces an audio effect of the leakage signal on the second ear of the user, an in-ear speaker coupled to the audio interface for providing an in-ear audio signal to the second ear of the user, in response to the filtered signal and the second input signal, an in-ear microphone for sensing a sensed audio signal, and a processor for updating an impulse response of the adaptive filter in order to reduce a contribution of the leakage signal to the sensed audio signal. | 12-01-2011 |
20120002819 | AUDIO DRIVER SYSTEM AND METHOD - A grounding switch is described which operates properly even in the presence of negative voltages on a signal line. The grounding switch uses isolated field effect transistors that have their substrates tied to different voltages. The isolated field effect transistor has gate voltage and substrate voltage which can be pulled down to negative voltage when the signal line has a negative voltage allowing the switch to remain open even with a negative voltage. | 01-05-2012 |
20120057719 | ADAPTIVE FILTER IN A SENSOR ARRAY SYSTEM - Disclosed is a steerable sensor array that receives input from a target and applies an averaging filter. An adaptive filter is then used if the SNR of the output of the averaging filter reaches a threshold. | 03-08-2012 |
20120057720 | AUDIO NOISE CANCELLING - A noise canceling system comprises a microphone ( | 03-08-2012 |
20120076316 | Microphone Array System - A method and system for enhancing a target sound signal from multiple sound signals is provided. An array of an arbitrary number of sound sensors positioned in an arbitrary configuration receives the sound signals from multiple disparate sources. The sound signals comprise the target sound signal from a target sound source, and ambient noise signals. A sound source localization unit, an adaptive beamforming unit, and a noise reduction unit are in operative communication with the array of sound sensors. The sound source localization unit estimates a spatial location of the target sound signal from the received sound signals. The adaptive beamforming unit performs adaptive beamforming by steering a directivity pattern of the array of sound sensors in a direction of the spatial location of the target sound signal, thereby enhancing the target sound signal and partially suppressing the ambient noise signals, which are further suppressed by the noise reduction unit. | 03-29-2012 |
20120087509 | METHOD OF DETERMINING PARAMETERS IN AN ADAPTIVE AUDIO PROCESSING ALGORITHM AND AN AUDIO PROCESSING SYSTEM - A method and an audio processing system determine a system parameter, e.g. step size, in an adaptive algorithm, e.g. an adaptive feedback cancellation algorithm so as to provide an alternative scheme for feedback estimation in a multi-microphone audio processing system. A feedback part of the system's open loop transfer function is estimated and separated in a transient part and a steady state part, which can be used to control the adaptation rate of the adaptive feedback cancellation algorithm by adjusting the system parameter, e.g. step size parameter, of the algorithm when desired system properties, such as a steady state value or a convergence rate of the feedback, are given/desired. The method can be used for different adaptation algorithms such as LMS, NLMS, RLS, etc. in hearing aids, headsets, handsfree telephone systems, teleconferencing systems, public address systems, etc. | 04-12-2012 |
20120140942 | Reduced delay digital active noise cancellation - A digital active noise cancellation circuit device ( | 06-07-2012 |
20120140943 | OVERSIGHT CONTROL OF AN ADAPTIVE NOISE CANCELER IN A PERSONAL AUDIO DEVICE - A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to measure the ambient sounds and transducer output near the transducer, thus providing an indication of the effectiveness of the noise canceling. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether the ANC circuit is incorrectly adapting or may incorrectly adapt to the instant acoustic environment and/or whether the anti-noise signal may be incorrect and/or disruptive and then take action in the processing circuit to prevent or remedy such conditions. | 06-07-2012 |
20120170766 | ANC For BT Headphones - An active noise cancellation controller for performing noise attenuation in a system over a predetermined frequency range, the active noise cancellation controller comprising: a first input for receiving a reference signal indicative of a noise level; a second input for receiving an error signal indicative of a remnant noise level; an output for providing a noise cancellation signal to a system in which noise attenuation is to be performed; a fixed feedback controller having a fixed infinite impulse response filter arranged for operation on an error signal received at the second input; a fixed feedforward controller having a fixed infinite impulse response filter arranged for operation on a reference signal received at the first input; and an adaptive feedforward controller having a digital adaptive finite impulse response filter arranged for operation on a reference signal received at the first input and on an error signal received at the second input, the coefficients of the digital adaptive filter being determined by: in the frequency domain, independently generating a set of initial coefficients for each of a plurality of subbands into which the predetermined frequency range is divided, said sets of initial coefficients being generated in accordance with a predetermined adaptive algorithm; and transforming said sets of initial coefficients into the time domain for use as the said coefficients of the digital adaptive filter; wherein the fixed feedback controller, fixed feedforward controller and adaptive feedforward controller are arranged to, in use, provide a noise cancellation signal at the output in dependence on a reference signal received at the first input and an error signal received at the second input. | 07-05-2012 |
20120213380 | Method and Device for Cancelling Acoustic Echo by Audio Watermarking - A method of cancelling acoustic echo in a first signal comprising an echo signal of a second signal, comprising: inserting, in an inaudible manner, into the second signal a pseudo-random sequence whose circular autocorrelation comprises a unit impulse and a continuous component; characterizing, in the first signal, by means of the inserted sequence, an acoustic channel followed by the echo signal; estimating the echo signal in the first signal by means of the characterization of the acoustic channel; and cancelling the echo signal by means of the obtained estimation. | 08-23-2012 |
20120230506 | ACTIVE NOISE REDUCTION ADAPTIVE FILTER ADAPTATION RATE ADJUSTING - A method for determining leakage factors or adaptation rates, or both, for adaptive filters in an active noise reduction system. The leakage factor or adaptation rate, or both, may vary depending on a parameter of an input reference signal. The parameter may include one or more of reference signal input frequency, rate of change of reference input signal frequency, if a predetermined triggering condition exits, or if a predetermined event has occurred. | 09-13-2012 |
20120308024 | BANDLIMITING ANTI-NOISE IN PERSONAL AUDIO DEVICES HAVING ADAPTIVE NOISE CANCELLATION (ANC) - A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit that performs the adaptive noise canceling (ANC) function also either adjusts the frequency response of the anti-noise signal with respect to the reference microphone signal, and/or by adjusting the response of the adaptive filter independent of the adaptation provided by the reference microphone signal. | 12-06-2012 |
20120308025 | ADAPTIVE NOISE CANCELING ARCHITECTURE FOR A PERSONAL AUDIO DEVICE - A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal that measures the ambient audio and an error microphone signal that measures the output of an output transducer plus any ambient audio at that location and injects the anti-noise signal at the transducer output to cause cancellation of ambient audio sounds. A processing circuit uses the reference and error microphone to generate the anti-noise signal, which can be generated by an adaptive filter operating at a multiple of the ANC coefficient update rate. Downlink audio can be combined with the high data rate anti-noise signal by interpolation. High-pass filters in the control paths reduce DC offset in the ANC circuits, and ANC coefficient adaptation can be halted when downlink audio is not detected. | 12-06-2012 |
20120308026 | FILTER ARCHITECTURE FOR AN ADAPTIVE NOISE CANCELER IN A PERSONAL AUDIO DEVICE - A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cancel ambient audio sounds. A processing circuit implements one or more adaptive filters that control the generation of the anti-noise signal. At least one of the adaptive filters is partitioned into a first portion having a fixed frequency response and a second portion having a variable frequency response. The partitioned filter may be an adaptive filter that generates the anti-noise signal directly from the reference microphone signal. An error microphone may be provided to measure the ambient sounds and transducer output near the transducer, and a secondary path adaptive filter included to generate an error signal from the error microphone signal, which may be partitioned, alone or in combination. | 12-06-2012 |
20120308027 | CONTINUOUS ADAPTATION OF SECONDARY PATH ADAPTIVE RESPONSE IN NOISE-CANCELING PERSONAL AUDIO DEVICES - A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Noise is injected either continuously and inaudibly below the source audio, or in response to detection that the source audio is low in amplitude, so that the adaptation of the secondary path estimating adaptive filter can be maintained, irrespective of the presence and amplitude of the source audio. | 12-06-2012 |
20120308028 | BANDLIMITING ANTI-NOISE IN PERSONAL AUDIO DEVICES HAVING ADAPTIVE NOISE CANCELLATION (ANC) - A personal audio device, such as a wireless telephone, includes noise canceling that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. The anti-noise signal is adaptively generated to minimize the ambient audio sounds at the error microphone. A processing circuit that performs the adaptive noise canceling (ANC) function also filters one or both of the reference and/or error microphone signals, to bias the adaptation of the adaptive filter in one or more frequency regions to alter a degree of the minimization of the ambient audio sounds at the error microphone. | 12-06-2012 |
20120328118 | FEEDBACK CONTROL IN A LISTENING DEVICE - A listening device includes a) an input transducer; and b) an output transducer for converting a processed electric signal to an output sound; a forward signal path being defined there between and comprising c) a signal processing unit for processing an electric input signal or a signal derived therefrom and providing a processed output signal; d) a manually operable user interface located on the listening device allowing a user to control a function of the listening device; e) a feedback estimation system for estimating a feedback path from the output transducer to the input transducer, the feedback estimation system comprising e1) an adaptive filter having e11) a variable filter part and e12) an algorithm part comprising an adaptive algorithm. | 12-27-2012 |
20130016846 | Systems and Methods for Area Efficient Noise Predictive Filter CalibrationAANM Tan; WeijunAACI LongmontAAST COAACO USAAGP Tan; Weijun Longmont CO USAANM Fitzpatrick; KellyAACI SudburyAAST MAAACO USAAGP Fitzpatrick; Kelly Sudbury MA US - Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes: a noise predictive filter circuit, a mean calculation circuit, a summation circuit, and a filter tap adaptation circuit. The noise predictive filter circuit is operable to perform a noise predictive filtering process on a data input based upon a selector input to yield a noise predictive output. The selector input is derived from a data detector output. The mean calculation circuit is operable to average two or more instances of the noise predictive output to yield a mean output. The summation circuit is operable to subtract the mean output from the noise predictive output to yield a sum output. The filter tap adaptation circuit is operable to adaptively calculate a filter tap based at least in part on a value derived from the data input and a value derived from the sum output. | 01-17-2013 |
20130070936 | CONTROL OF AN ADAPTIVE FEEDBACK CANCELLATION SYSTEM BASED ON PROBE SIGNAL INJECTION - Method and audio processing system determine a system parameter sp in a gain loop of an audio processing system. An alternative scheme is provided for feedback estimation in a multi-microphone audio processing system comprising an injected probe signal. The problem is solved in that a) an expression of an approximation of the expected square of the stationary loop gain, LG | 03-21-2013 |
20130083939 | METHOD AND APPARATUS FOR REDUCING THE EFFECT OF ENVIRONMENTAL NOISE ON LISTENERS - A method and apparatus for enhancing a desired audio signal for delivery through an electroacoustic channel include obtaining a noise estimate attributable to an external disturbance, applying the noise estimate to a dynamic noise compensation (DNC) process to thereby condition the desired audio signal as a function of the spectral characteristics of the noise estimate, applying the noise estimate to an adaptive equalization (AEQ) process to thereby condition the desired audio signal as a function of the electroacoustic response of the electroacoustic channel, and applying the noise estimate to an active noise cancellation (ANC) process configured to generate anti-noise for delivery into the electroacoustic channel. | 04-04-2013 |
20130129108 | TUNABLE ACTIVE NOISE CONTROL - An active noise control system and method for tuning an acoustic noise signal at a listening position are disclosed in which a first weighting element is connected in the filter coefficient copy path and/or a second weighting element is connected in the microphone path. | 05-23-2013 |
20130136271 | Method for Determining a Noise Reference Signal for Noise Compensation and/or Noise Reduction - The invention provides a method for determining a noise reference signal for noise compensation and/or noise reduction. A first audio signal on a first signal path and a second audio signal on a second signal path are received. The first audio signal is filtered using a first adaptive filter to obtain a first filtered audio signal. The second audio signal is filtered using a second adaptive filter to obtain a second filtered audio signal. The first and the second filtered audio signal are combined to obtain the noise reference signal. The first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal. | 05-30-2013 |
20130142349 | METHOD, DEVICE AND SYSTEM FOR ELIMINATING NOISES WITH MULTI-MICROPHONE ARRAY - To solve the problems with the prior art that a multi-microphone array cannot inhibit broad-band noises well and cannot be used in the increasingly widespread broad-band communication, embodiments of the present invention disclose a method, a device and a system for eliminating noises with multi-microphone array. The method according to an embodiment of the present invention comprises according to the number of different spacings between each of pairs of microphones of the multi-microphone array, dividing a full frequency band into the same number of sub-bands; decomposing signals of each of the pairs of microphones with the different spacings into a corresponding one of the sub-bands, wherein the larger the spacing between each pair of microphones is, the lower the frequencies of the sub-band into which the signals of the pair of microphones are decomposed will be; adaptively reducing the noises in the decomposed signals of each of the pairs of microphones with the different spacings in the corresponding sub-band to obtain noise-reduced signals for each of the sub-bands; and synthesizing the noise-reduced signals of each of the sub-bands to obtain a signal in which the noises have been reduced with the multi-microphone array in the full frequency band. The embodiments of the present invention can be used in scenarios of hands-free video calls. | 06-06-2013 |
20130259252 | ACTIVE VIBRATION OR NOISE SUPPRESSION SYSTEM - Provided is an active vibration or noise suppression system capable of converging vibration or noise more quickly. | 10-03-2013 |
20130279712 | ACTIVE VIBRATION NOISE CONTROL DEVICE, ACTIVE VIBRATION NOISE CONTROL METHOD AND ACTIVE VIBRATION NOISE CONTROL PROGRAM - An active vibration noise control device obtains error signals corresponding to a cancellation error between vibration noise and control sounds generated by multiple speakers, from microphone(s), and actively controls the vibration noise. A basic signal generating unit generates a basic signal based on a vibration noise frequency. An adaptive notch filter unit generates control signals provided to each of the multiple speakers by applying a filter coefficient to the basic signal. A reference signal generating unit generates a reference signal from the basic signal based on multiple transfer characteristics from the multiple speakers to the one or more microphones. A filter coefficient updating unit updates the filter coefficient used by the adaptive notch filter unit so as to minimize the error signals. A controlling unit changes amplitude of the control signals of the speakers based on a similarity between the transfer characteristics and characteristics of the vibration noise. | 10-24-2013 |
20130301847 | SEQUENCED ADAPTATION OF ANTI-NOISE GENERATOR RESPONSE AND SECONDARY PATH RESPONSE IN AN ADAPTIVE NOISE CANCELING SYSTEM - A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate to the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Adaptation of adaptive filters is sequenced so that update of their coefficients does not cause instability or error in the update. A level of the source audio with respect to the ambient audio can be determined to determine whether the system may generate erroneous anti-noise and/or become unstable. | 11-14-2013 |
20130301848 | DOWNLINK TONE DETECTION AND ADAPTATION OF A SECONDARY PATH RESPONSE MODEL IN AN ADAPTIVE NOISE CANCELING SYSTEM - An adaptive noise canceling (ANC) circuit adaptively generates an anti-noise signal from a reference microphone signal that is injected into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone proximate the speaker provides an error signal. A secondary path estimating adaptive filter estimates the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Tones in the source audio, such as remote ringtones, present in downlink audio during initiation of a telephone call, are detected by a tone detector using accumulated tone persistence and non-silence hangover counting, and adaptation of the secondary path estimating adaptive filter is halted to prevent adapting to the tones. Adaptation of the adaptive filters is then sequenced so any disruption of the secondary path adaptive filter response is removed before allowing the anti-noise generating filter to adapt. | 11-14-2013 |
20130301849 | ERROR-SIGNAL CONTENT CONTROLLED ADAPTATION OF SECONDARY AND LEAKAGE PATH MODELS IN NOISE-CANCELING PERSONAL AUDIO DEVICES - A personal audio device, such as a wireless telephone, generates an anti-noise signal from a microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. The microphone measures the ambient environment, but also contains a component due to the transducer acoustic output. An adaptive filter is used to estimate the electro-acoustical path from the noise-canceling circuit through the transducer to the at least one microphone so that source audio can be removed from the microphone signal. A determination of the relative amount of the ambient sounds present in the microphone signal versus the amount of the transducer output of the source audio present in the microphone signal is made to determine whether to update the adaptive response. | 11-14-2013 |
20140072134 | ROBUST PROCESS FOR MANAGING FILTER COEFFICIENTS IN ADAPTIVE NOISE CANCELING SYSTEMS - A system for managing the changing state of an adaptive filter in an active noise control (ANC) system is described. An adaptive filter state storage stores copies of prior states of the adaptive filter. A disturbance detector can detect either normal ambient noise or abnormal ambient noise. An adaptive filter state manager signals that a copy of a current state of the adaptive filter is to be repeatedly written to the state storage, so long as normal ambient noise is being detected. But when abnormal noise is detected, the state manager signals that the adaptive filter be restored to one of its prior states, from the copies stored in the state storage. Other embodiments are also described and claimed. | 03-13-2014 |
20140072135 | PREVENTION OF ANC INSTABILITY IN THE PRESENCE OF LOW FREQUENCY NOISE - An active noise control (ANC) processor has an adaptive filter that uses a reference signal to produce an anti-noise signal, and an error signal to evaluate cancellation performance. An adaptive filter algorithm engine configures the filter coefficients of the adaptive filter, in accordance with pre-shaped versions of the error and reference signals. The pre-shaping filter has a high-pass transfer function and enables the adaptive algorithm engine to increase noise cancellation performance in a high frequency band during the presence of focused or narrow-band noise energy in a low frequency band. Other embodiments are also described and claimed. | 03-13-2014 |
20140086425 | ACTIVE NOISE CANCELLATION USING MULTIPLE REFERENCE MICROPHONE SIGNALS - In one aspect, multiple adaptive W filters and associated adaptive filter controllers are provided that use multiple reference microphone signals to produce multiple, “component” anti-noise signals. These are gain weighted and summed to produce a single anti-noise signal, which drives an earpiece speaker. The weighting changes based on computed measures of the coherence between content in each reference signal and content in an error signal. Other embodiments are also described and claimed. | 03-27-2014 |
20140126739 | ACTIVE VIBRATION NOISE CONTROL APPARATUS - An active vibration noise control apparatus with which vibration noise can be reduced stably and effectively by preventing divergence of a filter coefficient or a delay in convergence due to an effect of a transfer characteristic on a secondary path. The active vibration noise control apparatus according to the present invention calculates an update step size in accordance with a magnitude of a gain in the transfer characteristic corresponding to a frequency of vibration noise, where the transfer characteristic is on the secondary path for propagation of a secondary vibration noise for reducing the vibration noise, and updates the filter coefficient on the basis of the calculated update step size. | 05-08-2014 |
20140146977 | METHOD OF CONTROLLING AN UPDATE ALGORITHM OF AN ADAPTIVE FEEDBACK ESTIMATION SYSTEM AND A DECORRELATION UNIT - An audio processing device comprises a feedback estimation system for estimating feedback from an output transducer to an input transducer, the feedback estimation system comprising an adaptive filter comprising a variable filter part for filtering an input signal according to variable filter coefficients and an algorithm part comprising an adaptive algorithm for dynamically updating filter coefficients, a control unit for controlling the de-correlation unit and the adaptive algorithm, and a correlation detection unit for determining a) the auto-correlation of a signal of the forward path and providing an AC-value and/or b) the cross-correlation between two different signals of the forward path and providing an XC-value. | 05-29-2014 |
20140233750 | SYSTEMS, METHODS, APPARATUS, AND COMPUTER-READABLE MEDIA FOR ADAPTIVE ACTIVE NOISE CANCELLATION - An adaptive active noise cancellation apparatus performs a filtering operation in a first digital domain and performs adaptation of the filtering operation in a second digital domain. | 08-21-2014 |
20140254816 | CONTENT BASED NOISE SUPPRESSION - Apparatus and methods for audio noise attenuation are disclosed. An audio signal analyzer can determine whether an input audio signal received from a microphone device includes a noise signal having identifiable content. If there is a noise signal having identifiable content, a content source is accessed to obtain a copy of the noise signal. An audio canceller can generate a processed audio signal, having an attenuated noise signal, based on comparing the copy of the noise signal to the input audio signal. Additionally or alternatively, data may be communicated on a communication channel to a separate media device to receive at least a portion of the copy of the noise signal from the separate media device, or to receive content-identification data corresponding to the content source. | 09-11-2014 |
20140270226 | ADAPTIVE MODULATION FILTERING FOR SPECTRAL FEATURE ENHANCEMENT - Techniques described herein are directed to the enhancement of spectral features of an audio signal via adaptive modulation filtering. The adaptive modulation filtering process is based on observed modulation envelope autocorrelation coefficients obtained from the audio signal. The modulation envelope autocorrelation coefficients are used to determine parameters of an adaptive filter configured to filter the spectral features of the audio signal to provide filtered spectral features. The parameters are updated based on the observed modulation envelope autocorrelation coefficients to adapt to changing acoustic conditions, such as signal-to-noise ratio (SNR) or reverberation time. Accordingly, such acoustic conditions are not required to be estimated explicitly. Techniques described herein also allow for the estimation of useful side information, e.g., signal-to-noise ratios, based on the observed spectral features of the audio signal and the filtered spectral features, which can be used to improve speaker identification algorithms and/or other audio processing algorithms. | 09-18-2014 |
20140307889 | ADAPTIVE VIBRATION DAMPING MECHANISM TO ELIMINATE ACOUSTIC NOISE IN ELECTRONIC SYSTEMS - A system to eliminate acoustic noise caused by a first MLCC (Multi-Layer Ceramic Capacitor) array positioned on a PCB (printed circuit board) is disclosed. The first MLCC array generates a first vibration responsible for the acoustic noise in response to receiving a varying input voltage. A third MLCC array senses the first vibration and generates a feedback signal. An adaptive filter then uses the feedback signal to generate an output signal that is used by a second MLCC to generate a second vibration that acts as a counter to dampen the first vibration. Because the input voltage signal is varying in time, the adaptive filter continually samples the varying input voltage and the feedback signal to generate the output signal that minimizes the acoustic noise. The second and third MLCC arrays are selectively positioned and oriented on the PCB for optimum performance. | 10-16-2014 |
20140307890 | SYSTEMS AND METHODS FOR ADAPTIVE NOISE CANCELLATION INCLUDING SECONDARY PATH ESTIMATE MONITORING - In accordance with methods and systems of the present disclosure, a processing circuit may implement at least one of: a feedback filter having a response that generates at least a portion of an anti-noise component from a playback corrected error, the playback corrected error based on a difference between the error microphone signal and a secondary path estimate; and a feedforward filter having a response that generates at least a portion of the anti-noise signal from a reference microphone signal. The processing circuit may also implement a secondary path estimate filter configured to model an electro-acoustic path of a source audio signal and have a response that generates a secondary path estimate from the source audio signal and a secondary path estimate performance monitor for monitoring performance of the secondary path estimate filter in modeling the electro-acoustic path. | 10-16-2014 |
20140314246 | SYSTEMS AND METHODS FOR HYBRID ADAPTIVE NOISE CANCELLATION - In accordance with systems and methods of this disclosure, a method may include generating a feedforward anti-noise signal component from a result of measuring with the reference microphone countering the effects of ambient audio sounds at an acoustic output of a transducer by filtering an output of the reference microphone, adaptively generating a feedback anti-noise signal component from a result of measuring with an error microphone for countering the effects of ambient audio sounds at the acoustic output of the transducer by adapting a response of a feedback adaptive filter that filters a synthesized reference feedback to minimize the ambient audio sounds in the error microphone signal, wherein the synthesized reference feedback is based on a difference between the error microphone signal and the feedback anti-noise signal component. | 10-23-2014 |
20140341388 | ADAPTIVE AUDIO EQUALIZATION FOR PERSONAL LISTENING DEVICES - An audio processor has an active noise cancellation (ANC) processor to compute an S-filter, which estimates a transfer function from an earpiece speaker, that is to be worn by a user, to an error microphone. The ANC processor adaptively produces an anti noise signal for reducing ambient noise that can be heard by the user. An adaptive equalization (EQ) processor has an EQ filter controller that adjusts an EQ filter, while audio user content is being filtered in accordance with the EQ filter before being fed to the speaker and then heard by the user. Other embodiments are also described and claimed. | 11-20-2014 |
20140369517 | SYSTEMS AND METHODS FOR DETECTION AND CANCELLATION OF NARROW-BAND NOISE - In accordance with methods and systems of the present disclosure, an integrated circuit for implementing at least a portion of a personal audio device may include an output including an anti-noise signal, a reference microphone input, an error microphone input, and a processing circuit. The processing circuit may implement an adaptive filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener, wherein the processing circuit may implement a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal and the reference microphone signal by adapting the response of the adaptive filter in accordance with a calculated narrow-band-to-full-band ratio, wherein the narrow-band-to-full-band ratio is a function of a narrow-band power of the reference microphone signal divided by a full-band power of the reference microphone signal. | 12-18-2014 |
20150071453 | ANC SYSTEM WITH SPL-CONTROLLED OUTPUT - An anti-noise signal is produced in accordance with an active noise cancellation process (ANC), at an input of a speaker so as to control how much background noise a user can hear. Strength of the anti-noise signal is adjusted gradually, rather than abruptly, in proportion to decreasing or increasing sound pressure level (SPL) of the background noise, during inactivation or activation of the ANC process. Other embodiments are also described and claimed. | 03-12-2015 |
20150071454 | HEARING AID, LOUDSPEAKER, AND FEEDBACK CANCELLER - A hearing aid includes: a microphone; a hearing aid processing unit configured to provide a gain to a first signal based on an output signal from the microphone to generate a second signal; a receiver configured to convert the second signal into sound; an adaptive filter configured to adaptively estimate a transfer function corresponding to a pathway from an input side of the receiver to an output side of the microphone; and a feedback removal unit configured to subtract a third signal generated based on the transfer function from the output signal of the microphone to obtain a signal and output the signal as the first signal; and a control unit configured to control the gain setting unit and an adaptive speed of the adaptive filter. | 03-12-2015 |
20150078572 | SYSTEMS AND METHODS FOR ADAPTIVE NOISE CANCELLATION BY ADAPTIVELY SHAPING INTERNAL WHITE NOISE TO TRAIN A SECONDARY PATH - A processing circuit may include: (i) an adaptive filter having a response that generates an anti-noise signal from a reference microphone signal, wherein the response is shaped in conformity with the reference microphone signal and a playback corrected error, and wherein the playback corrected error is based on a difference between an error microphone signal and a secondary path estimate; (ii) a secondary path estimate filter configured to model an electro-acoustic path of a source audio signal and having a response that generates a secondary path estimate from the source audio signal; (iii) a secondary coefficient control block that shapes the response of the secondary path estimate filter in conformity with the source audio signal and the playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error; and (iv) a noise injection portion for injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error. | 03-19-2015 |
20150104032 | MIC COVERING DETECTION IN PERSONAL AUDIO DEVICES - A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether one of the reference or error microphones is obstructed by comparing their received signal content and takes action to avoid generation of erroneous anti-noise. | 04-16-2015 |
20150117658 | PARTICULAR SIGNAL CANCEL METHOD, PARTICULAR SIGNAL CANCEL DEVICE, ADAPTIVE FILTER COEFFICIENT UPDATE METHOD, ADAPTIVE FILTER COEFFICIENT UPDATE DEVICE, AND COMPUTER PROGRAM - By using the adaptive filter, the reference input signal is processed so as to identify a pseudo-signal of a particular signal to be deleted. The pseudo-signal is subtracted from the mixture containing a target signal inputted from a microphone, the particular signal to be deleted, and a noise so as to obtain an error signal. A stationary noise is estimated to obtain a stationary noise estimated value. A non-stationary noise is estimated to obtain a non-stationary noise estimated value. The stationary noise estimated value is mixed with the non-stationary estimated value to obtain a mixed noise estimated value. An update amount is calculated according to a correlation value between the error signal and the reference input signal, and the mixed noise estimated value. According to the update amount, a coefficient of the adaptive filter is updated. | 04-30-2015 |
20150296296 | FREQUENCY-SHAPED NOISE-BASED ADAPTATION OF SECONDARY PATH ADAPTIVE RESPONSE IN NOISE-CANCELING PERSONAL AUDIO DEVICES - A personal audio device includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Noise is injected so that the adaptation of the secondary path estimating adaptive filter can be maintained, irrespective of the presence and amplitude of the source audio. The noise is shaped by a noise shaping filter that has a response controlled in conformity with at least one parameter of the secondary path response. | 10-15-2015 |
20150372650 | AUDIO DRIVER SYSTEM AND METHOD - An audio driver equipped with a distortion compensation unit corrects for detected distortion and includes a digital to analog converter (DAC), an amplifier, and an output driver that drives a loudspeaker. Between the output driver and the loudspeaker, the audio driver can include a series resistor and a differential amplifier to measure the voltage across the resistor. A distortion detection unit can use the detected voltage to determine whether distortion, such as rub and buzz distortion is present. The distortion detection unit can comprise an analog to digital converter (ADC) to digitize the voltage data, an FFT to transform the voltage data into frequency information, a root-mean-square (RMS) module that measures the energy at each frequency, and an analysis module which looks for the distortion signature in the energy spectrum. | 12-24-2015 |
20150382107 | ADAPTIVE DETECTOR AND AUTO MODE FOR DYNAMICS PROCESSOR - A dynamic processor for compressing an incoming audio signal is provided. The processor includes an adaptive detector, an adaptive module, and an amplifier. The adaptive detector includes a first adaptive filter and is configured to apply a transfer function to the incoming audio signal to generate a detector output signal. The adaptive module includes a second adaptive filter and is configured to generate a control signal based on the detector output signal. The amplifier is configured to receive the control signal from the adaptive module and to generate a compressed audio signal based on the control signal. | 12-31-2015 |
20160005389 | NOISE CANCELLATION WITH DYNAMIC RANGE COMPRESSION - An audio processor ( | 01-07-2016 |
20160012815 | ACTIVE VIBRATION/NOISE CONTROL APPARATUS | 01-14-2016 |
20160125866 | VARIABLE RATE ADAPTIVE ACTIVE NOISE CANCELLATION - A method of audio signal processing includes determining a difference between a first set of filter parameters of a first input frame of an active noise cancellation (ANC) filter and a second set of filter parameters of a second input frame of the ANC filter. The method further includes selectively modifying a duty cycle of adaptive ANC processing associated with the ANC filter based on the difference between the first set of filter parameters and the second set of filter parameters. | 05-05-2016 |
20160140949 | WRIST WEARABLE APPARATUSES AND METHODS WITH DESIRED SIGNAL EXTRACTION - Systems and methods are described to extract desired audio from an apparatus to be worn on a user's wrist. The apparatus includes a wrist wearable device, configured to be worn on the user's wrist. The wrist wearable device includes a first microphone. The first microphone has a first response pattern. The first microphone is coupled to the wrist wearable device. The first microphone is positioned on the wrist wearable device to receive a voice signal from a user when the wrist wearable device is on the user's wrist. | 05-19-2016 |
20160163303 | ACTIVE NOISE CONTROL AND CUSTOMIZED AUDIO SYSTEM - An audio customization system responsive to one or more inputs that enhance aspects of an audio output and one or more inputs that diminish aspects of an audio output. The system is set up to be able to lessen the influence of ambient audio or in some situations enhance ambient audio over source audio. The system may specify aspects of audio to be modified by specification of filtering algorithm, characterization of audio samples, monitored distortion, user selection, location specification or environmental specification. | 06-09-2016 |
20160171964 | FEEDBACK CANCELATION FOR ENHANCED CONVERSATIONAL COMMUNICATIONS IN SHARED ACOUSTIC SPACE | 06-16-2016 |
20160196816 | DOWNLINK TONE DETECTION AND ADAPTATION OF A SECONDARY PATH RESPONSE MODEL IN AN ADAPTIVE NOISE CANCELING SYSTEM | 07-07-2016 |
20180025717 | ESTIMATING SECONDARY PATH MAGNITUDE IN ACTIVE NOISE CONTROL | 01-25-2018 |